# Fermat’s Principle of Least Time. Effects

Published 11.11.2010
Presenter Anton Pankratov

Fermat’s Principle of Least Time. Effects.

Let’s consider some of effects of the least time principle which evokes a great deal of interest.

The first effect is the principle of reciprocity.

Let’s assume that we have already found the shortest way from A to B; then let’s go in the opposite direction (assuming that the light speed does not depend on the direction) ...